1. The Field of the Invention
The present invention is directed generally to methods and apparatus for effectuating surgical incisions. More specifically, the present invention is related to methods and apparatus for effectuating precise and uniform aortic incisions.
2. The Relevant Technology
Coronary artery bypass surgery is commonly required when coronary arteries narrowed by cholesterol-rich fatty deposits or plaques are unable to supply the heart muscle with a sufficient amount of blood, and as a result, the heart becomes starved for oxygen. Left untreated, coronary artery disease ultimately leads to acute myocardial infarction, commonly referred to as a heart attack. In coronary artery bypass surgery, a surgeon grafts a section of a healthy vessel, such as a portion of a saphenous vein, to bypass a stenotic or partially blocked portion of a coronary artery in order to ameliorate the oxygen access to the heart muscle.
Various techniques have been used to create the opening in the aorta, known as an aortotomy, to which the graft is sutured. Most aortotomies used for bypass grafts are created using a surgical scalpel in concert with an aortic punch. The surgical scalpel is used to make a linear incision in the aorta. Then, a portion of the aortic punch known as the "anvil" is passed through the incision. The punch is then engaged creating an aortotomy.
Conventionally, in order for the anvil of the punch to pass through the linear incision, either the incision needs to be longer than the diameter of the anvil or the hole created by the incision needs to be stretched. When the incision is made longer than the punch diameter, lateral nicks in the circumference of the aortotomy are created. These lateral nicks necessitate either repunching the aorta to enlarge the aortotomy or special suturing to avert bleeding at the lateral incision sites. Alternatively, when the initial hole created by the incision is stretched, often by utilizing a dilator prior to inserting the punch, an irregular and unpredictable tearing of the aorta often occurs.
The brittle and fragile nature of the aorta in the average coronary artery bypass graft patient necessitates great care in dealing with the aortic wall. The problems associated with conventional aortotomies can cause major problems with bleeding, compromise of the anastomosis, or aortic dissection.